|Color Case Hardening and Suhler
Traditional Surface Treatments on Hunting and Sporting Guns..
It is well known that iron is not very resistible due to its natural
softness and missing of surface protection. To prevent these bad
features, all iron parts of the guns, except for the barrel, are
treated to reach a higher level of carbon (steel) in the surface.
In the manufacturing of guns, this treatment is made by case hardening.
Animal charcoal, mainly leather charcoal is used as cementide powder
– sometimes we also use charcoaled claws, horn, ivory, etc.
The heating in the leather charcoal changes the iron surface to
steel. By the very quick cooling, the steel becomes harder and also
gets the special marble colours during the cooling process.
Especially the beautiful marble colours of the case hardening have
been a feature of the nicest finish of luxury guns in the last few
years. Even for the best craftsmen it is impossible to make them
as desired. So it is independent of the capacity or incapacity of
the craftspeople themselves. That is why it is impossible to forecasting
which gun will have more beautiful or more common colours. –
But the longer and more detailed your experience is, the more you
will be able to influence a quite little bit the appearance of the
marble colours of the iron parts.
Friedrich Brandeis 1881